Experiments on cholesterol metabolism will be done in laboratory animals. These studies are designed to determine whether the excretory function of the gastrointestinal tract can be utilized to deplete the body of excess cholesterol. Recent studies in our laboratory indicate that hydrophobic detergents inhibit entry of cholesterol into the body from the small intestine by blocking the transport of absorbed lipids from the mucosal cells and into lymph. Electron micrographic studies will be done on intestinal samples from detergent treated laboratory animals to determine where this block of lipid transport develops. Studies will also be done using radioactively labeled detergent to determine whether this agent has to be absorbed into the mucosal cell to exert its effect on lipid transport and, if so, whether the detergent itself is also transported out of the mucosal cells and into the body.